Some medical research facilities and pharmaceutical manufacturers keep large numbers of animals for testing purposes. Large numbers of cages are required to house the animals, and each cage must be cleaned periodically for the comfort and health of the animals. Because of the number of cages that need to be periodically cleaned, such facilities utilize washers for cleaning the animal cages. A typical washer used to clean animal cages is a tunnel washer.
Tunnel washers for cleaning animal cages are elongated structures that include a linear conveyor system, such as a belt type conveyor, for transporting the animal cages through one or more washing zones that are disposed along the length of the tunnel washer. Tunnel washers for cleaning animal cages are fixed and stationary. Tunnel washers for cleaning animal cages generally operate by directing jets or streams of fluid toward the animal cages from spray heads or nozzles located within the washer. The fluid is directed toward the animal cages(s) as the conveyor transports the animal cage(s) through the washing zones.
Operators that load animal cages into the tunnel washer work from work platforms that are also fixed and stationary. Prior to lifting an animal cage and placing it within the tunnel washer, an operator manually removes water bottles, feeding trays, bedding, and debris from each cage to be washed. Once the animal cage has been emptied, the operator inverts the cage and places it onto the conveyor at an entrance of the tunnel washer.
Repetitive motion, such as manual lifting and placing animal cages on a conveyor, can result in injury to a human operator. In order to reduce operator injuries, the National Institute for Occupational Safety and Health (NIOSH) has established guidelines to be used in designing manual lifting operations for industrial applications. The NIOSH guidelines indicate that the actual height of an operator's hands above a floor (i.e. “knuckle height”) at the end of a lifting task is one factor that should be considered to make a task easier for an operator. According to NIOSH standards, an optimum knuckle height is dependent upon the height of each operator. The actual knuckle height, i.e. position of the operator's hands at the end of a particular lift, is determined by several work environment factors. Work environment factors relating to loading a tunnel washer include: the shape, size, and weight of the animal cage; placement and design of handholds upon the animal cage; and the height of the work surface on which the animal cage is to be placed.
One problem with loading a conventional tunnel washer is that an appropriate work surface height for one operator may not be appropriate for another operator. Therefore, the risk of repetitive use injuries cannot be minimized for loading a conventional tunnel washer.
The present invention addresses this and other problems and provides an apparatus and a method for ergonomically loading a tunnel washer.